Systems and methods for efficient transfer of semiconductor elements

ABSTRACT

Systems and methods for efficient transfer of elements are disclosed. A film which supports a plurality of diced integrated device dies can be provided. The plurality of diced integrated device dies can be disposed adjacent one another along a surface of the film. The film can be positioned adjacent the support structure such that the surface of the film faces a support surface of the support structure. The film can be selectively positioned laterally relative to the support structure such that a selected first die is aligned with a first location of the support structure. A force can be applied in a direction nonparallel to the surface of the film to cause the selected first die to be directly transferred from the film to the support structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/389,157, filed on Dec. 22, 2016, which claims priority to U.S.Provisional Patent Application Nos. 62/278,354, filed Jan. 13, 2016, and62/303,930, filed Mar. 4, 2016, the entire contents of each of which arehereby incorporated by reference herein in their entirety and for allpurposes.

BACKGROUND Field

The field relates generally to systems and methods for the efficienttransfer of semiconductor elements to a support structure, and inparticular, for the efficient transfer of integrated devices dies from afilm to a support structure.

Description of the Related Art

Integrated device dies are typically built on a semiconductor wafer,which is placed on a film (e.g., a tape or other adhesive film) anddiced to define a plurality of separate integrated device dies. Inconventional semiconductor processes, the diced integrated device diesare removed individually from the dicing tape and placed onto anintermediate carrier, such as a die tray, waffle pack or otherprocessing apparatus. For example, in some arrangements, a robotic armis used to individually pick and place the dies from the die tray to theintermediate carrier. The device dies may undergo further processingand/or may be moved from the intermediate carrier to other processingstations, and ultimately to a packaging platform, such as a packagesubstrate (e.g., printed circuit board, leadframe, etc.).

However, the use of robotic pick-and-place machines may be inefficientand time-consuming, as the end effector of the machine may take severalseconds to individually remove each die from the dicing tape and placeit on a particular location of the intermediate carrier. Moving dies oneat a time using pick-and-place machines may therefore increase overallprocessing times and/or create a bottleneck in processing, whichincreases manufacturing costs. In some arrangements, a reel-to-reel tapemachine may be used to move dies from a dicing tape to an intermediatecarrier. However, reel-to-reel machines only move and array dies in onedimension (i.e., from one reel directly to another in a lineardirection).

Accordingly, there remains a need for improved systems and methods forthe efficient transfer of selected dies from a film to a supportstructure.

SUMMARY

In one embodiment, a method for mounting dies on a support structure isdisclosed. The method can include providing a film which supports aplurality of singulated elements or integrated device dies, theplurality of singulated elements or integrated device dies disposedadjacent one another along a surface of the film. The method cancomprise positioning the film adjacent the support structure such thatthe surface of the film faces a support surface of the supportstructure. The method can include selectively positioning the filmlaterally relative to the support structure such that a selected firstelement or die is aligned with a first location of the supportstructure. The method can include applying a force in a directionnonparallel to the surface of the film to cause the selected first dieto be directly transferred from the film to the support structure.

In another embodiment, a method for bonding integrated device dies isdisclosed. The method can include providing a film which supports afirst plurality of singulated integrated device dies, the firstplurality of singulated integrated device dies disposed adjacent oneanother along a first surface of the film. The method can includeproviding a support structure which supports a second plurality ofintegrated device dies, the second plurality of integrated device diesdisposed adjacent one another along a second surface of the supportstructure. The method can also include positioning the film adjacent thesupport structure such that a selected first die from the firstplurality of singulated integrated device dies or elements is alignedwith and faces a second die from the second plurality of singulatedintegrated device dies. The method can include applying a force in adirection nonparallel to the first surface of the film to cause thefirst die to contact the second die. The method can include directlybonding the first die with the second die, or a first element with asecond element. The method can also include removing the first die fromthe film.

The embodiments disclosed herein can be used to transfer any suitabletype of element. The element can comprise a semiconductor element or anelement that does not include a semiconductor material. For example, theelements may comprise a component that can be attached to a surface of asupport structure for any suitable purpose, including electrical and/ornon-electrical functions. Electrical circuits may be fabricated into,over, or around the element after attachment to the support structure.The singulated elements may comprise a plurality of singulatedintegrated device dies in some embodiments. The methods disclosed hereincan further comprise selecting a first known good element (e.g., a firstknown good die) from the plurality of singulated elements, the firstknown good element having properly-functioning non-electricalcharacteristics, the selected first element comprising the first knowngood element.

In yet another embodiment, a semiconductor processing system isdisclosed. The system can include a control system configured to selecta first die from a plurality of singulated integrated device dies orelement on a surface of a film which supports the plurality ofsingulated integrated device dies. The control system can be configuredto send instructions to a movable apparatus to cause the movableapparatus to position the film adjacent a support structure such thatthe surface of the film faces a support surface of the supportstructure. The control system can be configured to send instructions tothe movable apparatus to cause the movable apparatus to selectivelyposition the film laterally relative to the support structure such thata selected first die is aligned with a first location of the supportstructure. The control system can be configured to send instructions toa die release assembly to cause the die release assembly to apply aforce to at least one of the support structure and the film in adirection nonparallel to the surface of the film to cause the selectedfirst die to be transferred from the film to the support structure.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described herein. Of course, it is to be understood that notnecessarily all such objects or advantages may be achieved in accordancewith any particular embodiment of the invention. Thus, for example,those skilled in the art will recognize that the invention may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught or suggested herein withoutnecessarily achieving other objects or advantages as may be taught orsuggested herein.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments will becomereadily apparent to those skilled in the art from the following detaileddescription of the preferred embodiments having reference to theattached figures, the invention not being limited to any particularembodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

These aspects and others will be apparent from the following descriptionof preferred embodiments and the accompanying drawing, which is meant toillustrate and not to limit the invention, wherein:

FIG. 1 is a schematic top plan view of a packaging support structure anda wafer mount, according to one embodiment.

FIG. 2 is a top plan view of the wafer mount of FIG. 1 disposedvertically over the support surface of the support structure.

FIG. 3 is a top plan view of a die release assembly disposed over thewafer mount, according to some embodiments.

FIG. 4 is a top plan view of the support structure at various stages ofa wafer-level packaging process.

FIG. 5 is a schematic side view of a die release assembly comprising oneor more fluid actuators disposed over and in close proximity to thewafer mount, according to various embodiments.

FIG. 6A is a schematic side view of a die release assembly disposed overa wafer mount and packaging support surface, according to someembodiments.

FIG. 6B is a schematic side view of a die release assembly disposed overa wafer mount and packaging support surface, according to someembodiments.

FIG. 6C is a schematic top plan view of a fluid actuator with nozzlescomprising a plurality of polygonal orifices arranged adjacent oneanother along the fluid actuator.

FIG. 6D is a schematic top plan view of a fluid actuator with nozzlesarranged in a two dimensional array of rectangular or square orifices.

FIG. 6E is a schematic top plan view of a fluid actuator with roundednozzles arranged in a two-dimensional array.

FIG. 6F is a schematic top plan view of a fluid actuator with polygonalnozzles arranged adjacent one another, according to various embodiments.

FIG. 6G is a schematic top plan view of a fluid actuator with roundednozzles arranged in a two-dimensional array, according to variousembodiments.

FIG. 7 is a flowchart illustrating a method for mounting dies on apackaging support structure, according to one embodiment.

FIGS. 8A is a schematic side cross-sectional view of a wafer comprisinga substrate, a nonconductive layer deposited on the substrate, and aplurality of conductive contacts formed in the nonconductive layer.

FIG. 8B is a schematic side cross-sectional view of a handle waferattached to the substrate over the nonconductive layer and the contacts.

FIG. 8C is a schematic side cross-sectional view of the substrate thatis thinned to a desired thickness.

FIG. 8D is a schematic side cross-sectional view of the wafer withanother nonconductive layer and another set of contacts formed on thepolished backside of the wafer.

FIG. 8E is a schematic side cross-sectional view of the wafer mounted ona wafer mount.

FIG. 8F is a schematic side cross-sectional view of the wafer afterdicing into a plurality of integrated device dies.

FIG. 8G is a schematic side cross-sectional view of the structure aftera temporary adhesive is removed from backsides of the dies.

FIG. 8H is a schematic side cross-sectional view of integrated devicedies with bonding surfaces being exposed to a nitrogen-containingplasma.

FIG. 8I is a schematic side cross-sectional view of integrated devicedies after being transferred from the film directly to a supportstructure.

FIG. 8J is a schematic side cross-sectional view of a plurality ofbonded dies which are stacked and directly bonded to one another.

FIG. 8K is a schematic side cross-sectional view of the exposed activesurface of the bonded dies being prepared for direct bonding to anotherset of device dies.

FIG. 8L is a schematic side cross-sectional view of a third set of diesdirectly bonded to the stack of bonded dies.

FIG. 8M is a schematic side cross-sectional view of dies that aretransferred from a film to a waffle pack, according to variousembodiments.

FIG. 8N is a schematic side cross-sectional view of dies that areexposed to a nitrogen-containing plasma while disposed in the wafflepack.

FIG. 8O is a schematic side cross-sectional view of dies after beingflipped over into another waffle pack.

FIG. 9 is a flowchart illustrating a method for bonding integrateddevice dies, according to one embodiment.

FIG. 10A is a schematic side view of various systems and methods for theefficient transfer of integrated device dies from a film to a supportstructure using a pair of cooperating collets.

FIG. 10B is a schematic side view of the system of FIG. 10A, with thecollets being moved towards one another.

FIG. 10C is a schematic side view of the system of FIG. 10B, with thecollets engaging the dies and film.

FIG. 10D is a schematic side view of the system of FIG. 10C after thecollets are moved away from one another.

FIG. 10E is a schematic side view of the collets, according to variousembodiments.

DETAILED DESCRIPTION

Various embodiments disclosed herein relate to the efficient transfer ofelements (e.g., semiconductor elements such as integrated device dies)from a film, such as an adhesive film or tape, to a support structurefor packaging. As explained above, conventional systems may usepick-or-place machines to individually move elements or dies or othersemiconductor elements to intermediate carriers with a robotic arm,and/or reel-to-reel tape systems. Such systems can be inefficient,leading to increased manufacturing costs. The embodiments disclosedherein advantageously improve the efficiency of transferring dies (orother types of elements or semiconductor elements) from dicing tape to asupport structure for packaging. Moreover, the systems and methodsdescribed herein can identify known good dies (KGDs), which are diesthat have been tested to confirm proper electrical functionality. Thesystems and methods disclosed herein can advantageously place selecteddies at a desired location on a two-dimensional support surface usingtwo-dimensional indexing and actuation.

For example, in various embodiments, a wafer comprising a plurality ofelements (such as integrated device dies) can be diced or singulated ona dicing film, and KGDs (or other selected dies) of the wafer can beselectively transferred to a selected location on a two-dimensionalsupport surface. In various arrangements, the dicing film can bestretched or maintained in tension when supporting the dies. In someembodiments, the KGDs or selected dies can be transferred directly fromthe dicing film to a packaging platform, which can comprise a packagesubstrate (such as a printed circuit board, or PCB, leadframe, ceramicsubstrate, interposer etc.), another integrated device die (e.g., by wayof stacking and direct bonding), an adhesive film for reconstitution ofa wafer for packaging, a panel or any other suitable platforms.Advantageously, therefore, in various embodiments, there may be nointermediate carrier to transport the dies from the dicing film tosubsequent processing stations and/or the packaging platform. Instead,selected singulated or diced integrated device dies or elements from asubstrate or the wafer (such as KGDs) can be directly and selectivelyplaced on the ultimate packaging platform from the dicing film withoutintervening structures, while unselected dies or elements can be leftbehind on the dicing film. Among other advantages, handling of the diesis minimized and surfaces can be prepared for direct bonding in apackaging structure (e.g., die stack) with fewer steps for protectingthe prepared surface before bonding. In other embodiments, the selectedsingulated or diced integrated device dies (such as KGDs) can beselectively placed on an intermediate carrier (such as an adhesive sheetor tape), which can be employed for intervening packaging steps (e.g.,molding for reconstituting a wafer for fan-out metallization) and/orsubsequently mount the selected dies to the packaging platform.

The embodiments disclosed herein describe various ways to efficientlytransfer integrated device dies to a packaging structure. However, itshould be appreciated that the methods and systems disclosed herein canbe used to efficiently transfer any suitable type of element (such as asemiconductor element, including integrated device dies, etc.) to apackaging structure. For example, the embodiments disclosed herein canbe used to transfer semiconductor elements such as integrated devicedies, interposers (e.g., semiconductor elements with integratedconductive traces or vias for transferring signals to and from otherelements), reconstituted dies, etc. In some embodiments, other types ofelements (which may or may not comprise a semiconductor material) can betransferred to a packaging structure. For example, the embodimentsdisclosed herein can transfer optical devices, such as lenses, filters,waveguides, etc. Moreover, in the embodiments disclosed herein, theelements (e.g., semiconductor elements) can be processed for directbonding while mounted on the dicing film, such that most or all of thedirect bonding processes can be conducted with the semiconductorelements mounted on the dicing film. Processing the elements for directbonding on the dicing film can improve the overall efficiency ofbonding, as intermediate transfer of the elements to other structuresbetween singulation and direct bonding can thereby be avoided.

FIG. 1 is a schematic top plan view of a support structure or surface 10and a wafer mount 12. The wafer mount 12 can comprise an assemblyconfigured to support a semiconductor wafer 18 during varioussemiconductor processing techniques. For example, the wafer mount 12 canbe configured to support the wafer 18 during a singulating or dicingoperation. The wafer mount 12 can comprise a frame 14 and a film 15mounted to the frame 14. The film 15 can comprise an adhesive sheet,e.g., a sheet of tape. The film 15 can be secured to the frame 14 aboutthe periphery of the film 15 such that the film 15 is in tension.Although the frame 14 is illustrated as a polygonal frame in FIG. 1, itshould be appreciated that the frame can take any suitable physical formthat is configured to support the film 15.

The wafer 18 can comprise a semiconductor material (such as silicon orany other suitable Group elements) that is patterned with a plurality ofintegrated devices organized into multiple associated integrated devicedies 16. For example, the wafer 18 may be patterned to define integratedcircuits such as processors or memory, microelectromechanical systems(MEMS) device dies or any other suitable type of integrated device knownto the skilled artisan. In addition, in some embodiments, eachintegrated device can be tested on the wafer 18 prior to singulating ordicing to identify which device dies 16 are electronically functional,referred to herein as known good dies (KGDs), and which device dies 16are damaged or otherwise dysfunctional, and to generate a map locatingKGDs. In other embodiments, electrical testing may be performed aftersingulating or dicing. Testing the electrical and/or electroniccharacteristics of the device dies 16 before the dies 16 are moved tothe subsequent support structure 10 can advantageously reduce the amountof real estate on the support structure 10 which is used fordysfunctional or damage dies. Thus, in various embodiments disclosedherein, only KGDs may be selected and placed on the support structure10, which can reduce manufacturing costs associated with processing andplacing damaged or dysfunctional dies.

The wafer 18 can be mounted to the wafer mount 12 prior to singulatingor dicing, such that the wafer 18 is adhered to an adhesive surface ofthe film 15. In some embodiments, the backside of the wafer can bemounted to an adhesive surface of the film 15. The wafer 18 can be dicedor singulated using a suitable dicing or singulation technique to dividethe wafer 18 into a plurality of separate, diced integrated device dies16. For example, the wafer 18 can be sawed or otherwise singulated tocreate the individual dies 16. The dicing operation can be conductedsuch that only the wafer 18 is diced and the film 15 remainscontinuously connected (even though there may be saw or other marks onthe film 15 as a result of the dicing operation) to support the dies 16.The intact film 15 can be used to keep the singulated dies 16 aggregatedadjacent one another on an adhesive surface of the film 15. The film 15and/or the singulated dies 16 can be cleaned using any suitable type ofcleaning method. As explained above, although the wafer 18 of FIG. 1includes integrated device dies 16 or element, in other embodiments,other types of semiconductor elements (such as interposers,reconstituted dies, etc.) may be provided on the wafer 18.

The support structure 10 can be any suitable structure or surfaceconfigured to support the diced integrated device dies 16 transferredfrom the wafer mount 12. For example, in the illustrated embodiment, thesupport structure 10 can comprise a support surface 11 coupled to,formed with, and/or mounted on a movable apparatus, such as a movabletable. The support surface 11 can comprise a packaging platform, such asa package substrate (e.g., PCB, plastic, glass, leadframe, ceramicsubstrate, etc.), a wafer or stack of wafers, an interposer, areconstituted wafer, panel, or reconstituted panel, or one or more otherintegrated device dies. As discussed in more detailed below with respectto

FIGS. 8A-8L, the support surface to which the dies are transferred maybe die or wafer surfaces prepared for direct bonding, without anyintervening adhesive. In other embodiments, the support surface 11and/or the support structure 10 may comprise an intermediate carrier,such as an adhesive sheet or mechanical die carrier, which can be usedto transport the integrated device dies 16 to the ultimate packagingplatform. In some embodiments, the support surface 11 may be an adhesivelayer upon with a reconstituted wafer is formed, such that the relativepositions of dies 16 and other packaging materials (e.g., mold orencapsulating material) are fixed on the support surface 11. Inembodiments in which high die transfer rates are desirable, the supportstructure 10 and wafer mount 12 can move relative to each other.

As shown in FIG. 1, the support structure 10 and support surface 11 canbe movable in two dimensions, i.e., movable in the +x, −x and +y, −ydirections. A control system (see the control system 100 of FIGS. 5-6B)comprising one or more processors and associated memory devices can beconfigured to accurately and precisely control the movement of thesupport structure 10 in two dimensions. For example, the control systemcan be electrically coupled to a motor and gear system which can move orindex the support structure 10 so as to align selected locations of thesupport surface 11 with selected integrated device dies 16 on the wafermount 12.

FIG. 2 is a top plan view of the wafer mount 12 of FIG. 1 disposedvertically over the support surface 11 of the support structure 10. Insome embodiments, the wafer mount 12 with diced integrated device dies16 can be positioned over the support surface 11 using any suitablemechanism, such as a robotic arm assembly. In some embodiments, such asthat shown in FIG. 2, the wafer mount 12 with diced integrated devicedies 16 may remain stationary, and the support structure 10 may bemovable in two dimensions. In other embodiments, the support structure10 may remain stationary, and the wafer mount 12 with dies 16 may bemovable in two dimensions (i.e., the −x, +x and −y, +y directions). Instill other embodiments, both the support structure 10 and the wafermount 12 with diced die 16 may be movable in two dimensions. In theembodiment of FIG. 2, the support surface 10 and/or the wafer mount 12may be moved vertically relative to one another such that the dicedintegrated device dies 16 are disposed in close proximity to the supportsurface 11 of the support structure 10. For example, the diced dies 16can be spaced vertically from the support surface 11 by a distance in arange of 10 microns to 1000 microns, or more particularly, by a distancein a range of 10 microns to 100 microns. In addition, the supportstructure 10 may be moved laterally in two dimensions to align a desiredlocation of the support surface 11 with a selected integrated device die16. For example, the support structure 10 can be moved such that aselected KGD of the integrated device dies 16 (previously mapped afterwafer-level testing) is aligned laterally (i.e., in the x and ydirections) with the desired location of the support surface 11.

FIG. 3 is a top plan view of a die release assembly 20 disposed over thewafer mount 12, according to some embodiments. As shown in FIG. 3, thedie release assembly 20 can be movable in two dimensions, i.e., the xand y directions, parallel to the surface of the film. The die releaseassembly 20 can be moved over a selected die from the plurality of diceddies 16. As explained in detail below in connection with FIGS. 5-6G, thedie release assembly 20 can comprise one or more actuators (not shown inFIG. 3) configured to apply a force in a direction nonparallel to (e.g.,perpendicular to) the adhesive surface of the film 15 to cause theselected die to be directly transferred to the support surface 11 of thesupport structure 10 from the film 15. In some embodiments, the dierelease assembly 20 can include one actuator to release a correspondingdevice die 16 from the film 15. In such an arrangement, the supportstructure 10 can be moved so as to position the selected die directlyover a desired location on the support surface 11. The die releaseassembly 20 can be moved laterally (e.g., rotationally and/or linearlyin the x and/or y directions) to be positioned over the selected devicedie. The actuator can be activated to cause the corresponding selecteddie to be transferred directly to the support surface 11.

In other embodiments, however, the die release assembly 20 can comprisean array of multiple actuators configured to cause multiplecorresponding dies to be released from the film 15 and transferred tothe support structure 10. For example, in some embodiments, the dierelease assembly 20 can comprise a linear array of N×1 actuatorsarranged in a line, where N is any suitable positive integer. In such anarrangement, the die release assembly 20 can be moved along the xdirection to be positioned over one or more dies to be released from thedie mount 12. In other arrangements, the die release assembly 20 cancomprise a two-dimensional array of N×M actuators arranged so as tocause multiple dies across an area of the film 15 to be released. Itshould be appreciated that, in die release assemblies that have multipleactuators, the actuators can be activated together or individually. Insome arrangements, all the actuators of the assembly 20 can beactivated, e.g., simultaneously or sequentially (with or withoutintervening indexed motion). In other arrangements, only selectedactuators of the assembly 20 can be activated simultaneously. Forexample, actuators of the assembly 20 which are disposed over KGDs (asdetermined from prior wafer-level testing and mapping) may be activatedsuch that only KGDs are transferred to the support structure 10.

In some embodiments a trailing arm (not shown) similar to the dierelease assembly 20 may apply additional momentary pressurepneumatically to the KGD that is transferred to the support structure.Such additional momentary pressure may be particularly desirable forembodiments in which the support surface 11 comprises an adhesivematerial. For embodiments in which the support surface 11 comprises dieor wafer surfaces prepared for direct bonding, without any interveningadhesive, the additional momentary pressure can be omitted, or ifapplied such pressure need not be high (e.g., less than or equal toabout 2 atm), and may be applied for on the order of 1 millisecond to 1second in view of prior preparation of surfaces for direct bonding. Theadditional pneumatically applied pressure may be applied to every die onthe support structure 10 simultaneously in another supporting chamberwith or without heat (not shown).

FIG. 4 is a top plan view of the support structure 10 at various stagesof a wafer-level packaging process. In the embodiment of FIG. 4,multiple dies A-D can be mounted within corresponding package regions 21of the support structure 10. The corresponding package regions 21 may beassociated with the components that are ultimately packaged together inan integrated device package. Advantageously, the components of eachpackage can be assembled on the support structure 10, which may comprisea wafer or wafer stack, or an intermediate carrier such as an adhesivesheet or die carrier, directly from a first adhesive (e.g., wafer dicingtape). As shown in FIG. 4, Die A may be associated with Map A, which canidentify locations on the support surface 11 at which Die A should bemounted. The control system (see the control system 100 of FIGS. 5-6B)can instruct the movable support structure 10 and/or the wafer mount 12to move laterally relative to one another (e.g., rotationally and/orlinearly in the x and/or y directions) such that Die A is laterallyaligned with the identified location on Map A of the support surface 11.The die release assembly 20 can be activated to cause each Die A to betransferred to an identified location on the support surface 11. Thus,as shown in FIG. 4, each Die A can be mounted to a corresponding packageregion 21 in the upper left corner of the package region 21. Inaddition, as explained above, prior wafer-level die testing and mappingmay confirm that each Die A is a known good die, or KGD, such that onlyKGDs are disposed within each package region 21.

The die release assembly 20 can move parallel to the surface of the film15 to place additional dies on the support structure 10. The system canplace each Die B at associated locations on the support surface 11 asindicated by Map B (i.e., at the upper right corner of each packageregion 21), each die C at associated locations on the support surface 11as indicated by Map C (i.e., at the lower left corner of each packageregion 21), and each die D at associated locations on the supportsurface 11 as indicated by Map D (i.e., at the lower right corner ofeach package region 21). Thus, as shown in FIG. 4, each die A-Dassociated with a package can be mounted at the wafer level to anassociated package region 21 of the support surface 11. In addition,each die A-D mounted to the package regions 21 can be KGDs, so as toimprove the package yield, speed up the package assembly process, andreduce waste. The use of a movable support structure 10 for moving thesupport surface 11 relative to the wafer mount 12 (or vice versa) in twodimensions can advantageously enable the accurate placement of KGDs at adesired packaging location of the support structure 10.

As explained above, the support structure 10 can comprise any suitablestructure. For example, in some embodiments, the support structure 10comprises a packaging platform, such as a package substrate (e.g., PCB,plastic, glass, ceramic, lead frame, interposer, etc.). In someembodiments, the support structure 10 comprises a wafer or wafer stack,a die or die stack, or a reconstituted wafer. In still otherembodiments, the support structure 10 comprises an intermediate carrier,such as an adhesive sheet, upon which further packaging steps can betaken (e.g., molding for forming a reconstituted wafer). Furthermore,although the embodiment of FIG. 4 illustrates several selected dies A-Dbeing mounted side-by-side within corresponding package regions 21, insome embodiments, the selected dies (or some of the dies) may be stackedon top of one another, as will be clear from the example of FIGS. 8A-8L.One advantage of the disclosed embodiments is that binned devices withdesired characteristic within the KGDs mapped on the wafer 18 can beselectively clustered at selected locations on the support structure 10.KGDs with lower performances can be clustered and segregated to otherknown locations on the support structure 10. However, such a clusteringprotocol may be more time consuming and expensive to implement ascompared with dies that are mounted on a tape in a spool.

FIG. 5 is a schematic side view of a die release assembly 20 comprisingone or more fluid actuators 24 disposed over and in close proximity tothe wafer mount 12. The die release assembly 20 can be configured toapply a force to a backside of the film 15 directly opposite a selecteddie 16A to cause the selected die 16A to be transferred directly fromthe film 15 to the support surface 11. In various embodiments, the backside of the singulated dies may be exposed to a radiation source, suchas an ultraviolet (UV) source, to weaken the adhesion between the die16A and the dicing tape 15 prior to the transfer operation. For example,in the embodiment of FIG. 5, the fluid actuator 24 can comprise one ormore nozzles which direct a high velocity fluid against the backside ofthe film 15. The high velocity fluid can cause the film 15 with the die16A to flex away from the die release assembly 20 such that the die 16Acontacts the support surface 11. The pressure applied by the highvelocity fluid can also cause the die 16A to be released from the film15 and transferred directly to the support surface 11. The nozzle(s) ofthe actuator 24 can be sized and shaped so as to apply a force to alocalized region of the backside of the film 15 such that only theselected die is transferred from the film 15 to the support structure10. In some embodiments, the fluid supplied by the fluid actuator 24 cancomprise air or any other suitable gas, such as nitrogen. In otherembodiments, the fluid may comprise a liquid such as water. In variousembodiments, the fluid may be cooled or heated prior to or during thetransfer of the die 16A to the support structure 10. For example, thefluid may be heated to a temperature above 50° C., e.g., in a range of50° C. to 150° C. In some embodiments, heating the fluid mayadvantageously enhance the adhesion of the selected die 16A to thesupport surface 11 (e.g., directly bonding to another die) and/or mayhelp delaminate or remove the die 16A from the film 15.

The support surface 11 may be disposed on any suitable type of movableplatform, such as a movable table or support (see FIGS. 1-3 andattendant description). In the embodiment of FIG. 5, the support surface11 is supported by a movable support 22 comprising a rotating chuckassembly, which is configured to rotate the support surface 11 about a zaxis, which is perpendicular to the x and y directions. The movablesupport 22 can be moved (i.e., rotated) to accurately align a desiredlocation on the support surface 11 (e.g., a desired location within aparticular package region 21 as explained in FIG. 4) with a selected die16A. When the die 16A is aligned with the desired location on thesupport surface 11, the fluid actuator 24 can be activated to cause thedie 16A to be transferred from the film 15 to the support surface 11.Although the die release assembly 20 uses fluid actuators 24 to causethe dies to be released from the film 15 and transferred to the supportsurface 11, in other embodiments, such as those described below inconnection with FIGS. 81, the die release assembly 20 can comprise aplunger or other type of mechanical device which can apply a force in adirection nonparallel to the film. Other non-mechanical or non-contactapproaches, such as magnetic devices, sonic devices or radiationdevices, can be used to apply a force in a direction nonparallel to thefilm to transfer the die 16A to the support structure 10. For example inone embodiment a radiation device such as a laser source may be used todebond the die 16A from the film 15 in a direction nonparallel to thefilm. Also heat from the radiation source may improve the attachment andthe adhesion of the die 16A to the surface of the support structure 10.

As explained above, a control system 100 can be programmed to controlthe operation of the movable support 22 (and thereby the supportstructure 10 and support surface 11) and/or the operation of the dierelease assembly 20. For example, the control system 100 can compriseone or more processors and memory devices which are programmed withsoftware that, when executed, sends instructions to a motor (or otherdevice) which causes the movable support 22 to rotate to a desiredorientation. Furthermore, the control system 100 may store in memoryinformation regarding which dies of the wafer 18 (see FIG. 3) are KGDs,and may also store information regarding the target location of the dieson the support surface 11 (including, e.g., the wafer-level package mapsshown in FIG. 4). Based at least in part on this information, thecontrol system 100 can instruct the movable support 22 to move to adesired orientation for each die, or at least each KGD or a binned die,on the wafer 18 (see FIG. 3). The control system 100 can also beprogrammed to send instructions to a motor or other device to cause thedie release assembly 20 to be positioned over the die to be transferred.The control system 100 can instruct the die release assembly 20 to applya suitable force against the backside of the film 15 to cause the diesto be transferred to the support structure 10. The control system 100can instruct the die release assembly 20 to apply a suitable forceagainst the backside of the film 15 to cause the binned dies to betransferred to the support structure 10 in a clustered configuration,such that dies with desirable higher performance attributes (forexample, lower power, high frequencies) may be segregated to portions ofthe support layer where the beneficial process outcomes are expected.

FIG. 6A is a schematic side view of a die release assembly 20 disposedover a wafer mount 12 and support surface 11, according to someembodiments. Unless otherwise noted, reference numerals used in FIG. 6Arepresent components that are similar to or the same as componentsillustrated in FIGS. 1-5. For example, as shown in FIG. 6A, the wafermount 12 with integrated device dies 16 can be disposed in closeproximity relative to the support surface 11. As explained above, thesupport surface 11 can be aligned vertically (in the z direction) andlaterally (e.g., rotationally and/or linearly in the x and/or ydirections) such that selected dies 16A are laterally aligned with adesired location on the support surface 11 (which may correspond to adesired location within a package region 21). The control system 100 ofFIG. 6A may operate in a manner similar to that of the control system100 illustrated in FIG. 5.

In the embodiment of FIG. 6A, the die release assembly 20 comprises afluid actuator 24 having a plurality of nozzles. FIGS. 6C-6E areschematic top plan views of a fluid actuator 24 with nozzles 26 arrangedin nozzle patterns that can be used with the embodiment of FIG. 6A. Withreference to FIG. 6A, the fluid actuator 24 of the die release assembly20 can be activated to inject a high velocity fluid (e.g., a gas such asair, nitrogen, etc.) against the backside of the film 15. The nozzles 26of the fluid actuator 24 can be sized and shaped asymmetrically to causean edge 23 of a selected die 16A to contact the support surface 11before other regions of the die 16A. For example, as shown in FIG. 6C,the nozzles 26 can comprise a plurality of polygonal (e.g., rectangular)orifices arranged adjacent one another along the fluid actuator 24. Thenozzles 26 can be wider near a first end 23 a than at a second end 23 b.In FIG. 6C, the nozzles 26 are arranged in a single row of adjacentrectangular orifices. In FIG. 6D, the nozzles 26 are wider near a firstend 23 a than a second end 23 b, however, the nozzles 26 are arranged ina two dimensional array of rectangular or square orifices in which thewidth or major dimension of the nozzles 26 decreases from the first end23 a to the second end 23 b. In FIG. 6E, the nozzles 26 are similarlywider near a first end 23 a, but the nozzles 26 are arranged in atwo-dimensional array of rounded orifices (e.g., circular or elliptical)in which the width or major dimension of the nozzles 26 decreases fromthe first end 23 a to the second end 23 b.

When the nozzles 26 of FIGS. 6C-6E are actuated with the arrangementshown in FIG. 6A, the wider orifices near the first end 23 a can createfluid streams against the film 15 to cause the film 15 to move towardsthe support surface 11. Because the orifices of the nozzles 26 nearerthe first end 23 a are wider than at the second end 23 b, a higherflowrate of fluid is injected against the edge 23 of the die 16A ascompared to other regions of the die 16A. The higher flowrate of fluid(and therefore a higher applied force) at the edge 23 of the die 16A cancause the edge 23 of the die 16A to contact the support surface 11before other regions of the die 16A. Sufficient fluid pressure can beapplied to cause the dies 16A to delaminate from the film 15 andtransfer to the support surface 11.

FIG. 6B is a schematic side view of a die release assembly 20 disposedover a wafer mount 12 and support surface 11, according to someembodiments. Unless otherwise noted, reference numerals used in FIG. 6Brepresent components that are similar to or the same as componentsillustrated in FIGS. 1-6A. For example, as shown in FIG. 6B, the wafermount 12 with integrated device dies 16 can be disposed in closeproximity relative to the support surface 11. As explained above, thesupport surface 11 can be aligned vertically (in the z direction) andlaterally (to mapped x and y positions) such that selected dies 16A arelaterally aligned with a desired location on the support surface 11(which may correspond to a desired location within a package region 21or intermediate carrier surface). The control system 100 of FIG. 6B mayoperate in a manner similar to that of the control system 100illustrated in FIGS. 5-6A.

As with the embodiment of FIG. 6A, the die release assembly 20 of FIG.6B comprises a fluid actuator 24 having a plurality of nozzles. FIGS. 6Fand 6G are schematic top plan views of a fluid actuator 24 with nozzles26 arranged in a nozzle pattern that can be used with the embodiment ofFIG. 6B. The nozzles 26 of the fluid actuator 24 of FIG. 6B can be sizedand shaped to cause a central region 25 of a selected die 16A to contactthe support surface 11 before other regions of the die 16A, such as theedge 23 of the die 16A. As shown in FIG. 6B, in such arrangements, thecentral region 25 of the die 16A may bend or flex so as to contact thesupport surface 11 before the edge 23 of the die 16A. Referring to FIG.6F, the fluid actuator 24 can comprise a plurality of nozzles 26 withrectangular-shaped orifices. In FIG. 6F, the orifices may be widest at acentral region of the actuator 24 and narrower at the end regions.Similarly, in FIG. 6G, the nozzles 26 can comprise rounded (e.g.,circular or elliptical) orifices arranged in a two-dimensional array inwhich the larger orifices are arranged near the central region andsmaller orifices are arranged near the ends of the actuator 24.

When the actuator 24 of FIG. 6B is activated, the nozzles 26 near thecenter of the actuator 24 may supply a greater flowrate (and hence agreater force) than nozzles 26 near the edges of the actuator 24. Theincreased flowrate at the center of the actuator 24 may apply sufficientforce at the central region 25 of the die 16A to cause the centralregion 25 to bow or flex towards the support surface 11. The centralregion 25 can contact the support surface 11 before other regions of thedie 16A. The selected die 16A can be removed from the film 15 anddirectly transferred to the support surface 11.

FIG. 7 is a flowchart illustrating a method 30 for mounting dies on asupport structure, according to one embodiment. The method 30 begins ata block 32 in which a film supporting a plurality of diced elements(e.g., semiconductor elements such as diced integrated device dies) isprovided. As explained above in connection with FIG. 1, a wafer can bemounted to a film of a wafer mount. The wafer has been previouslyprocessed to have a plurality of integrated devices, which can be dicedor separated using any suitable method, such as sawing. After dicing,the film (e.g., a tape) can maintain the dies (or other elements orsemiconductor elements) such that they remain adjacent one another alongan adhesive surface of the film. In some embodiments, the device diescan be tested before dicing to determine and map which dies areelectronically functional, i.e., which dies are known good dies, orKGDs. In some embodiments, each integrated device die may comprise aplurality of contact pads formed thereon. During the processing steps ofFIG. 7, in some embodiments, the contact pads may be covered with apassivation film or exposed; however, the pads may be devoid of externalcontact bumps (such as solder balls).

Turning to a block 34, the film with the diced integrated devices (orother type of diced element or semiconductor element) is positionedadjacent a support structure such that an adhesive surface of the filmfaces a support surface of the support structure. As explained above,the support structure can comprise any suitable type of surface,including, e.g., a packaging platform (such as a package substrate,interposer, one or more device dies, one or more wafers) or anintermediate carrier (such as an adhesive sheet). In a block 36, thefilm can be selectively positioned laterally relative to the supportstructure such that a selected first die (or other type of element orsemiconductor element) is aligned with a first location of the supportstructure. As explained above, the support structure and/or the wafermount may be indexed to move in two-dimensions. A control system can beprogrammed to position the support structure relative to the film suchthat a selected die (e.g., a KGD) is aligned with a selected location onthe support surface, such as a corresponding package region of thesupport surface.

Moving to a block 38, a force can be applied in a direction nonparallelto the adhesive surface of the film to cause the selected die (or othertype of element or semiconductor element) to be directly transferredfrom the film to the support structure. For example, as explainedherein, a die release assembly can be moved over the selected die and anactuator can be activated to cause the die to be released from the filmand transferred to the support structure. In some embodiments, theactuator can comprise a fluid actuator having one or more nozzlesconfigured to inject a high velocity fluid (e.g., a gas such as air ornitrogen, or a liquid) against the backside of the film to cause the dieto be transferred to the support structure. The nozzles can be arrangedin any suitable pattern. For example, in some embodiments, the nozzlescan be arranged so as to cause an edge of the die to contact the supportsurface before other regions of the die. In other embodiments, thenozzles can be arranged so as to cause a central region of the die tobow and contact the support surface before other regions of the die. Instill other embodiments, the actuator can comprise a plunger or othermechanical actuator configured to apply a force nonparallel to the film.

Advantageously, the embodiments disclosed herein with respect to FIGS.1-7 can be used to efficiently transfer dies or other elements from adicing film directly to a support structure, which may be anintermediate carrier or a final packaging platform. Moreover, theembodiments disclosed in FIGS. 1-7 can enable package assemblers toutilize only KGDs in packages, which can improve package yield andreduce costs associated with using dysfunctional device dies. Further,the two-dimensional selective placement of selected dies on the supportstructure can enable the use of accurate and efficient wafer-levelpackaging in which KGDs are accurately and directly mounted to a surfacein which the die has a fixed relationship with other components of thepackage, such as another die or die stack, a wafer or wafer stack, apackage substrate, encapsulating or mold material to be formed aftertransfer onto the support structure, etc.

When the dies are assembled on the corresponding package regions of thesupport surface, the support surface can be molded by a filling materialor encapsulant which is applied over portions of the dies and/or in gapsbetween adjacent dies. In some arrangements, the backsides of the diescan be thinned. The support surface (which may comprise a wafer or a webof substrate material, such as PCB or lead frame) may be subsequentlysingulated to yield a plurality of singulated device packages.

FIGS. 8A-8L are schematic side cross-sectional views of various stagesof a method for bonding integrated device dies, according to someembodiments. It should be appreciated that the fluid actuator andrelative motion embodiments disclosed above with respect to FIGS. 1-7may also apply to the embodiment shown in FIGS. 8A-8L. For example, theflowchart in FIG. 7 illustrates steps of a manufacturing method whichalso apply to FIGS. 8A-8L. Moreover, although FIGS. 8A-8L illustratedirect bonding of integrated device dies, it should be appreciated thatthe methods can alternatively be used to direct bond other types ofsemiconductor elements, such as interposers, reconstituted dies, etc.FIG. 8A illustrates a wafer 18 comprising a substrate 40, anonconductive layer 42 deposited on the substrate 40, and a plurality ofconductive contacts 44 formed in the nonconductive layer 42. Thesubstrate 40 can comprise silicon or any other suitable semiconductormaterial, glass, ceramic, or a polymeric layer or panel. Thenonconductive layer 42 can comprise a suitable nonconductive material,such as, for example, inorganic or organic dielectric material, such assilicon dioxide, silicon carbide, diamond-like carbon, a polymericlayer, a composite material or various combinations of these materials,etc. Also, portions of the conductor 44 may be formed by damascene andnon-damascene metallization methods. The conductive contacts 44 can bedefined by a damascene process, in which the contacts 44 are filledinside trenches formed in the nonconductive layer 42, and may becoplanar with, slightly protrude above (e.g., 2-20 nm), or maybeslightly recessed below (e.g., 2-20 nm) below the surface of thenonconductive layer 42. The contacts 44 can comprise any suitableconductor, such as copper, gold, etc. The surfaces of the contacts 44and the nonconductive layer 42 can be prepared for direct bonding withanother wafer or other structure. For example, the surfaces of thecontacts 44 and/or the nonconductive layer 42 may be polished (using,e.g., chemical-mechanical polishing techniques) so as to ensure that thebonding surfaces are extremely smooth. Additional details regardingsurface preparations of the contacts 44 and nonconductive layer 42 maybe found throughout U.S. Pat. Nos. 6,902,987; 6,566,694; 7,109,092;6,962,835; and 8,389,378, the entire contents of each of which areincorporated by reference herein in their entirety and for all purposes.

Turning to FIG. 8B, a handle wafer 48 can be attached to the substrate40 over the nonconductive layer 42 and the contacts 44 by way of anadhesive 46. The handle wafer 48 can comprise silicon or anothersemiconductor material that is sufficiently thick so as to act as ahandle for moving or otherwise manipulating the wafer 18. In FIG. 8C,the backside of the substrate 40 can be thinned to a desired thicknesssuitable for the integrated device dies ultimately formed from the wafer18. For example, the substrate 40 can be thinned to a thickness in arange of 10 microns to 200 microns, in a range of 10 microns to 100microns, in a range of 20 microns to 75 microns, in a range of 25microns to 50 microns, or any other suitable thickness. The backside ofthe thinned wafer 18 can be polished or otherwise planarized in a mannersimilar to the front side of the wafer 18. In FIG. 8D, anothernonconductive layer 52 and another set of contacts 54 can be formed onthe polished backside of the wafer 18 in a manner similar to thecontacts 44 and nonconductive layer 42. The second set of contacts 54may communicate with integrated circuitry within the substrate 40 byway, for example, of through-silicon vias (TSVs) and/or back-end-of-line(BEOL) metallization. The nonconductive layer 52 and contacts 54 mayalso be polished and prepared for bonding as explained above.

In FIG. 8E, the wafer 18 can be mounted on a wafer mount 12, similar tothe wafer mount 12 described above in connection with FIGS. 1-7. Forexample, the wafer mount 12 can comprise a frame 14 and a film 15supported by the frame 14. The wafer 18 can be adhered to an adhesivesurface 55 of the film 15. In some embodiments, the wafer 18 can becoated with a protective polymer to protect the active surface of thewafer 18 from the film 15. In other embodiments, no protective coatingmay be used, and any residue from the film 15 may be subsequentlycleaned. The handle wafer 48 can be removed from the adhesive 46.

Turning to FIG. 8F, the wafer 18 can be diced into a plurality ofintegrated device dies 16. For example, the wafer 18 can be sawed,punched, or otherwise singulated so as to form the diced integrateddevice dies 16. As with the embodiments of FIGS. 1-7, the device dies 16can comprise any suitable type of die, such as an integrated circuit,such as memory or processor, a MEMS die, etc. As shown in FIG. 8F, thedicing operation may fully dice or singulate the dies 16, but leave thefilm 15 intact and continuous, although the dicing saw may leavescorings or markings on the film 15. The intact film 15 can support thediced dies 16 and maintain their relative positions on the film 15. InFIG. 8G, the adhesive 46 can be removed by any suitable method, such asby exposure to electromagnetic radiation (e.g., ultraviolet radiation)and/or a solvent.

In FIG. 8H, bonding surfaces 56 of the integrated device dies 16 can beplanarized (e.g., polished by chemical mechanical polishing), activated(e.g., very slightly etched) and/or terminated with a suitable species.For example, as shown in FIG. 8H, the bonding surfaces 56 (which maycomprise silicon oxide) can be exposed to nitrogen-containing plasma ina plasma chamber. For example, the plasma process can comprise areactive ion etching process in some embodiments. The very slight etchcan result in a root-mean-square micro-roughness of less than 0.5 nm,e.g., in a range of 0.1 nm to 3 nm. Beneficially, the processesdisclosed herein (e.g., polishing, activation, and/or termination) canbe performed while the dies 16 are mounted to the film 15, which canimprove the efficiency of the direct bonding processes. For example, theprocesses disclosed herein may be conducted at relatively lowtemperatures (e.g., in a range of 50° C. to 100° C.), which may be asufficiently low temperature and/or may be for sufficiently lowprocessing times (e.g. , less than 10 minutes, or less than 6 minutes)such that the film 15 can accommodate the direct bonding processeswithout degrading or melting. In other embodiments, the bonding surfaces56 can be exposed to a nitrogen-containing solution, e.g., anammonia-based solution. Terminating the bonding surfaces 56 withnitrogen-containing species can advantageously enhance the directbonding of the dies 16 to other semiconductor elements. Additionaldetails of activation and termination processes are disclosed throughoutU.S. Pat. No. 6,902,987, the entire contents of which are incorporatedby reference herein in their entirety and for all purposes.

Turning to FIG. 81, the integrated device dies 16 shown in FIGS. 8F-8Hcan be transferred from the film 15 directly to a support structure 10.In the illustrated embodiment of FIG. 81, the support structure 10 forthe dies 16 comprises a second set of dies 16B mounted on a second wafermount 12B comprising a second frame 14B which supports a second film15B. However, as with the embodiments of FIGS. 1-7, in other embodimentsthe support structure 10 can comprise any suitable type of structure,including, e.g., a packaging platform, such as a package substrate(e.g., PCB, glass, plastic, leadframe, ceramic substrate, siliconinterposer, etc.), a wafer or stack of wafers, a reconstituted wafer,panel, or reconstituted panel, etc. In other embodiments, the supportstructure 10 may comprise an intermediate carrier, such as an adhesivesheet or mechanical die carrier, which can be used for further packagingsteps (e.g., molding for wafer reconstitution) or to transport theintegrated device dies 16 to the ultimate packaging platform.

The first film 15 and dies 16 can be mounted to a first platform 62. Asshown in FIG. 81, the first film 15 and dies 16 can be inverted inpreparation for direct bonding with the second dies 16B. The second film15B to which the second dies 16B are adhered can be mounted to a secondplatform 64. The first and second platforms 62, 64 can comprise anysuitable structure for supporting the respective wafer mounts 12, 12B.In the illustrated embodiment, for example, the first and secondplatforms 62, 64 can comprise vacuum chucks which apply a negativepressure to each film 15, 15B so as to secure the films 15, 15B to therespective platforms 62, 64. In FIG. 81, the dies 16 from FIGS. 8F-8Hare illustrated in an inverted configuration, i.e., disposed over thesecond set of dies 16B. It should be appreciated, however, that in otherarrangements, the dies 16 from FIGS. 8F-8H may instead be disposed onthe second platform 64, and the dies 16B can be disposed on the firstplatform 62. Further, although the processing steps described above inconnection with FIGS. 8A-8H are described with reference to the dies 16,the same processing steps may also be applied to the surfaces of thesecond set of dies 16B in preparation for direct bonding, such asplanarization, activation and termination.

As with the embodiments of FIGS. 1-7, the control system 100 can storeinformation regarding each die 16, 16B that is to be bonded. Forexample, the control system 100 can determine which dies 16 on the firstfilm are KGDs. The control system 100 can also be configured to identifywhich individual dies 16 from the first set are to be bonded to whichindividual dies 16B from the second set. The control system 100 caninstruct a motor or other suitable apparatus to cause the first platform62 to move relative to the second platform 64 (or vice versa) so as tolaterally align a selected die 16 with a corresponding selected die 16Bfrom the second set. For example, as explained above, the first platform62 can be moved laterally in two dimensions (i.e., in the x and ydimensions, e.g., rotationally and/or linearly in the x and/or ydirections) to align the selected die 16 with the corresponding die 16Bin the lateral direction.

Once the dies 16, 16B are generally aligned, a die release assembly 24,under the control of the control system 100, can apply a force againstthe backside of the film 15 to cause the die 16 to be transferred fromthe film 15 to the support surface 11, which can also comprise a bondingsurface 56B of the corresponding second die 16B. For example, as shownin FIG. 81, the die release assembly 24 can comprise a plunger 60 whichis driven along the z direction to apply a contact force against thebackside of the film 15.

In some embodiments, the plunger 60 can apply an initial downward force(which may include pressure sensing) against the film 15 in the -zdirection to cause one die 16 to be disposed below the other dies 16.The plunger arrangement can comprise a displacement and/or pressuresensor with a feedback control system to accurately control the amountof force and/or displacement applied by the plunger 60. An alignmentsystem can be activated (by the control system 100 and/or a user) toestimate the degree of misalignment in the x, y, and/or z directions ofthe die 16 relative to the second die 16B. The alignment system cancommunicate with the control system 100 to provide feedback with respectto the degree of misalignment. The alignment system can comprise anoptical measurement system in some arrangements. For example, thealignment system can comprise one or more cameras in some embodiments.In other embodiments, an interferometric alignment system comprising oneor more lasers can be used. The control system 100 can iteratively sendcommands to cause the first platform 62 to move align the selected die16 relative to the second die 16B in two dimensions.

Precision movement of the plunger 60 (and/or the second platform 64)along the z-direction can cause the bonding surface 56 of the first dieto contact and directly bond with the corresponding bonding surface 56Bof the second die 16B. The direct bond between the dies 16, 16B cancomprise a chemical (e.g., covalent) bond in which the nonconductivelayers 42 and the contacts 44 of the respective dies 16, 16B are bondedto one another without an intervening adhesive. The direct bondingprocess may be conducted at room temperature in some embodiments. Thehigh degree of smoothness of the dies prior to bonding can improve thestrength of the direct bond. For example, prior to bonding the bondingsurfaces of the dies may have planarized surfaces with a surfaceroughness (RMS) in a range of 0.5 and 1.5 nm. In various embodiments, apost-bonding anneal may be performed (at a temperature in a range of100° C. to 400° C.) to further enhance the bonding. In variousembodiments, the direct bond can have a bond strength of at least 400mJ/m² (e.g., at least 2000 mJ/m²). Additional details of direct bondingprocesses may be found in U.S. Pat. Nos. 6,902,987; 6,566,694;7,109,092; 6,962,835; and 8,389,378, the entire contents of each ofwhich are incorporated by reference herein in their entirety and for allpurposes. In some embodiments, the plunger 60 may comprise one or moreinternal channels through which a fluid may be supplied. The fluid maycomprise a heated or cooled fluid which can enhance the bonding processduring the transfer of the dies 16.

Once the selected dies 16, 16B are directly bonded, the plunger 60 canbe retracted along the +z direction. The bonding force between the dies16, 16B may be greater than the adhesive force between the die 16 andthe film 15, such that retraction of the plunger 60 can cause the die 16to release from the film 15. In some arrangements, the adhesion betweenthe die 16 and film 15 may have been reduced by exposing the back sideof the film 15 to a radiation source, such as, for example, a UV lightor laser. Once the selected die 16 is released, the control system 100can instruct the plunger 60 and the first platform 62 to move to anotherpair of dies to be bonded until each die 16 (or each KGD) on the firstwafer mount 12 is transferred and bonded to an associated die 16B (whichmay also be a KGD) on the second wafer mount 12B. FIG. 8J illustrates aplurality of bonded dies 16C which are stacked and directly bonded toone another. The bonded dies 16C can remain attached to the second film15B and/or to the second platform 64 (not shown in FIG. 8J). Each diecan be bonded sufficiently to allow release from the film 15 in muchshorter time frames than, e.g., thermocompression bonding. The bond mayinclude non-conductive to non-conductive (e.g., oxide) surface chemicalbonding. Subsequent heating may enhance the non-conductive surfacebonding, and may also enhance or cause bonding of conductive surfaces ofaligned contacts 44 of the dies 16, 16B. Furthermore, the techniquesdescribed herein facilitate direct bonding of thinned dies 16, such asmay be difficult to handle by conventional pick-and-place robots.

Turning to FIG. 8K, the exposed active surface of the bonded dies 16Ccan comprise bonding surfaces 56C which can be prepared for directbonding to another set of device dies, in some embodiments. For example,as with FIG. 8H, the bonding surfaces 56C can be activated (e.g., byvery slight etching) and/or terminated with a suitable species while thedies 16C are mounted on the film 15. Activation and termination can beconducted sequentially or in a single process. For example, as shown inFIG. 8K, the bonding surfaces 56C can be exposed to nitrogen-containingplasma in a plasma chamber. In other embodiments, the bonding surfaces56 can be exposed to a nitrogen-containing solution, e.g., anammonia-based solution, as explained above. FIG. 8L illustrates a thirdset of dies 16D directly bonded to the dies 16C. The bonding of thethird dies 16D to the bonded dies 16C may be performed as explainedabove with respect to FIG. 81. The process can continue until thedesired number of dies are stacked and directly bonded to one another.As above, when the direct bonding is completed, the stacked dies can bepackaged in any suitable manner. For example, the dies can beencapsulated at least in part by a molding or filling material whichfills gaps between adjacent dies. The encapsulated dies can besingulated and mounted to a package substrate, such as a PCB, leadframe,ceramic substrate, etc. In other embodiments, the die stacks may alreadybe mounted on a packaging substrate or large process die, in place ofthe second film 15B, during the bonding process.

Thus, in the illustrated embodiment, semiconductor elements (e.g.,device dies 16) can be mounted to a film 15 for direct bondingprocesses. For example, as shown herein, the dies 16 can be diced on thefilm 15, polished on the film 15, and activated and/or terminated on thefilm 15. By processing the dies 16 on the film 15, the efficiency andefficacy of the direct bonding techniques can be improved.

FIGS. 8M-8O illustrate an alternative embodiment, which can be used inconjunction with, or as an alternative to, various steps of the processillustrated in FIGS. 8A-8L. For example, as shown in FIG. 8M, in someembodiments, the dies 16 can be transferred from the film 15 to a wafflepack 105 that has a plurality of recesses 106 formed therein. As shownin FIG. 8M, the dies 16 can be inverted and placed in the correspondingrecesses 106 with the bonding surfaces 56 facing upward. Turning to FIG.8N, various processing steps can be performed on the dies 16 in thewaffle pack 105, such as polishing, termination, and/or activation. Asshown in FIG. 8N, for example, the bonding surface 56 can be exposed toa nitrogen plasma to both activate and terminate for direct bonding.Beneficially, the waffle pack 105 can be made of a material which canundergo higher temperature processing for longer periods of time thanthe processes used in conjunction with the film 15. For example, thedies 16 can be heated to 300° C. to 400° C. when positioned in thewaffle pack 105. Turning to FIG. 80, the processed dies 16 can bepositioned (e.g., via a pick and place machine, or other system) incorresponding recesses of a waffle pack 105A, which may be differentfrom the waffle pack 105. For example, the waffle pack 105 of FIGS. 8Mand 8N may be flipped over so as to transfer the dies 16 to the wafflepack 105A. The dies 16 in FIG. 8O can be processed for stacking ofadditional dies or other semiconductor elements, as explained above.

FIG. 9 is a flowchart illustrating a method 90 for bonding elements(e.g., semiconductor elements such as integrated device dies), accordingto one embodiment. In a block 92, a film which supports a plurality ofdiced semiconductor elements (e.g., diced integrated device dies) isprovided. As with FIG. 7, the semiconductor elements can comprise anysuitable type of device die, such as a processor die, MEMS die, memorydie, etc., or may comprise an interposer, a reconstituted die, or anyother suitable type of semiconductor element. In other embodiments, theelements may comprise other types of devices or substrates, includingelements that may or may not comprise a semiconductor material. Thediced semiconductor elements can be disposed adjacent one another alonga first surface of the film. In embodiments in which the semiconductorelements comprise device dies, the dies may be tested for electricaland/or electronic functionality prior to dicing to identify KGDs. Thesemiconductor elements can be diced using any suitable technique, suchas sawing, punching, etc.

In a block 93, a support structure which supports a second plurality ofdiced semiconductor elements (e.g., integrated device dies) is provided.The second plurality of semiconductor elements (e.g., diced dies) can bedisposed adjacent one another along a second surface of the supportstructure. The semiconductor elements of the second plurality cancomprise any suitable type of device die, such as a processor die, MEMSdie, memory die, etc., or can comprise an interposer, a reconstituteddie, or other type of semiconductor element. In embodiments in which thesemiconductor elements comprise device dies, the dies of the secondplurality may be tested for electrical and/or electronic functionalityprior to dicing to identify KGDs. The semiconductor elements can bediced using any suitable technique, such as sawing, punching, etc.

In a block 94, the film can be positioned adjacent the support structuresuch that a selected first semiconductor element (which may be a KGD)from the first plurality of semiconductor elements is aligned with andfaces a second semiconductor element (which may also be a KGD) from thesecond plurality of diced semiconductor elements. The film can beselectively positioned laterally in two dimensions so as to align thefirst and second semiconductor elements. Various types of alignmentsystems (such as optical alignment systems) may be used to measure thedegree of misalignment between the two semiconductor elements.

Moving to a block 95, a force can be applied in a direction nonparallelto the first or second surfaces to cause the first semiconductor elementto contact the second semiconductor element. In some embodiments, theforce can be applied by a plunger which contacts the backside of thefilm. In other embodiments, the force can be applied by a high velocityfluid which is passed through one or more nozzles. The applied force cancause the first semiconductor element to be transferred to the secondsemiconductor element.

Turning to a block 96, the first semiconductor element can be directlybonded with the second semiconductor element. For example, as explainedabove, respective bonding surfaces of first and second device dies canbe prepared for bonding. The bonding surfaces may be polished,activated, and terminated with a desired species as explained herein.When the bonding surfaces are brought into contact (e.g., at roomtemperature), covalent bonds form between the two semiconductor elementswithout an intervening adhesive. In a block 98, the first semiconductorelement can be removed from the film. For example, the plunger can beretracted, which may cause the film to pull away from the firstsemiconductor element due to the stronger chemical bonds between the twodies.

The stacked and bonded semiconductor elements (e.g., stacked and bondeddies) can be packaged in any suitable way for subsequent incorporationinto a larger electronic device or system. For example, an encapsulantor molding material can be applied over at least part of a surface ofthe semiconductor elements and/or in gaps between adjacent semiconductorelements. The semiconductor elements can be singulated and mounted to apackage substrate.

FIGS. 10A-10E illustrate yet another embodiment of systems and methodsfor the efficient transfer of semiconductor elements (e.g., integrateddevice dies) from a film 15, such as an adhesive film or tape, to asupport structure 10 for packaging. Unless otherwise noted, referencenumerals in FIGS. 10A-10E refer to components that are the same as orgenerally similar to like-numbered components of FIGS. 1-8L. Moreover,the features described in connection with FIGS. 10A-10E may be used incombination with any of the features described and illustrated inconnection with the embodiments of FIGS. 1-9. In the embodiment of FIGS.10A-10E, the die release assembly 24 comprises a pair of collets 110A,110B that cooperate to hold or support two dies 16, 16B on respectivefilms 15, 15B that are to be bonded together. In some embodiments, thecollets 110A, 110B can cooperate to hold or support a single die that isto be placed on a support structure 10.

Turning to FIG. 10A, one or more dies 16 (which may comprise KGDs andpotentially also bad dies, which can be identified in wafer-leveltesting) may be supported on the film 15, and one or more dies 16B(which may also comprise KGDs and potentially also bad dies) may besupported on the film 15B. The films 15, 15B can be oriented relative toone another such that bonding surfaces 56 of the dies 16 facecorresponding bonding surfaces 56B (and support surfaces 11) of the dies16B. In FIG. 10B, the die release assembly 24 can be activated to applyrespective forces Fi, F2 to a first collet 110A and a second collet 110Bto cause the collets 110A, 110B to move towards one another along thez-axis. In some embodiments, one collet may remain stationary while theother collet is moved. Although not illustrated in FIG. 10B, the collets110A, 110B can be controlled by a control system, which may be the sameas or generally similar to the control system 100 disclosed herein. Asshown in FIG. 10B, as the collets 110A, 110B move towards one another,the collets 110A, 110B can pierce the films 15, 15B around the peripheryof the dies 16, 16B such that a portion of each collet 110A, 110B isdisposed about the periphery of the dies 16, 16B to support the dies 16,16B.

The collets 110A, 110B can comprise any suitable mechanism which holdsand supports the dies 16, 16B for bonding to one another and/or forplacement on the support structure 10. FIG. 10E is a schematic side viewof exemplary collets 110A, 110B, according to some embodiments. In FIG.10E, which is presented in the y-z plane, the first collet 110A cancomprise a plurality of fingers 112A spaced apart by one or morecorresponding gaps 114A. The second collet 110B can similarly comprise aplurality of fingers 112B spaced apart by one or more corresponding gaps114B. As shown in FIG. 10E, the collets are oriented with respect to oneanother such that the fingers 112A of the first collet 110A can bestaggered along the y-axis relative to the fingers 112B of the secondcollet 110B such that, when the collets 110A, 110B are brought togetheralong the z-axis, the fingers 112A of the first collet are received inthe gaps 114B of the second collet, and the fingers 112B of the secondcollet are received in the gaps 114A of the first collet. While only oneside of the collets is shown in FIG. 10E, it will be understood thatfingers can be similarly staggered on all four sides of the collets forsurrounding rectangular dies. Staggering the fingers 112A, 112B relativeto one another can advantageously enable the collets 110A, 110B to matein order to hold and/or support the dies 16, 16B. In addition, when thecollets 110A, 110B are brought together by application of the respectiveforces Fi, F2, the fingers 112A, 112B can pierce the films 15, 15B sothat the fingers 112A, 112B are disposed about the periphery of the dies16, 16B, while still leaving the films 15, 15B continuous and intact butwith perforations.

Returning to FIG. 10C, the collets 110A, 110B can be further broughttogether by application of the forces F₁, F₂ until the two dies 16, 16Bcontact and bond together, for example, by direct bonding using theprocessing techniques described herein. In the illustrated embodiment,the second collet 110B may remain stationary, or may move only slightly,and the first collet 110A may move along the −z axis, which can causethe film 15 to stretch or bend at a deformable portion 116 of the film15. After direct bonding, a bond 113 can form at an interface betweenthe two dies 16, 16B.

In FIG. 10D, the two collets 110A, 110B can be moved away from oneanother after bonding by application of respective forces F3, F4 to thecollets 110A, 110B. In some embodiments, one collet (such as collet110B) may remain stationary, and the other collet (e.g., collet 110A)may move away along the z-axis. When the collets 110A, 110B areseparated from one another, one film 15 may release from the die 16,while the other die 16B remains attached to the other film 15B. Forexample, after direct bonding, the strength of the direct bond mayexceed the adhesive strength between the die 16 and the film 15 suchthat, when the collets 110A, 110B are separated, the die 16 detachesfrom the film 15. In some arrangements, as explained above, apre-release treatment (such as exposure to UV radiation) may be appliedto the film 15 that is to be released.

Advantageously, the use of the collets 110A, 110B in FIGS. 10A-10E canprovide a reliable mechanism for holding and supporting the dies 16, 16Bbefore and during the bonding process. Moreover, the collets 110A, 110Bcan provide a simple alignment feature for accurately aligning the twodies prior to bonding, as machining and location of the fingers cansupply sufficient mechanical alignment of the dies for bonding, possiblywith the aid of inexpensive optical alignment with respect to one edgeof a die. In some other arrangements, more sophisticated optical sensors(e.g., cameras) may be used to align markers on the dies 16, 16B toensure that the dies 16, 16B are aligned before bonding. The collets110A, 110B may provide a simpler solution than such more sophisticatedoptical sensors, since the collets 110A, 110B can be accurately machinedto fit snugly around the periphery of the dies 16, 16B and to mate withone another to align the dies 16, 16B for bonding.

Although this invention has been disclosed in the context of certainembodiments and examples, it will be understood by those skilled in theart that the present invention extends beyond the specifically disclosedembodiments to other alternative embodiments and/or uses of theinvention and obvious modifications and equivalents thereof. Inaddition, while several variations of the invention have been shown anddescribed in detail, other modifications, which are within the scope ofthis invention, will be readily apparent to those of skill in the artbased upon this disclosure. It is also contemplated that variouscombinations or sub-combinations of the specific features and aspects ofthe embodiments may be made and still fall within the scope of theinvention. It should be understood that various features and aspects ofthe disclosed embodiments can be combined with, or substituted for, oneanother in order to form varying modes of the disclosed invention. Thus,it is intended that the scope of the present invention herein disclosedshould not be limited by the particular disclosed embodiments describedabove, but should be determined only by a fair reading of the claimsthat follow.

What is claimed is:
 1. A processing system comprising: a control systemconfigured to: select a first element from a plurality of singulatedelements on a surface of a film which supports the plurality ofsingulated elements; send instructions to a movable apparatus to causethe movable apparatus to position the film adjacent a support structuresuch that the surface of the film faces a support surface of the supportstructure; send instructions to the movable apparatus to cause themovable apparatus to selectively position the film laterally relative tothe support structure such that the first element is aligned with afirst location of the support structure; and send instructions to arelease assembly to cause the release assembly to apply a force to atleast one of the support structure and the film in a directionnonparallel to the surface of the film to cause the first element to betransferred from the film to the support structure, such that the firstelement is removed from the film.
 2. The processing system of claim 1,further comprising the movable apparatus.
 3. The processing system ofclaims 1, further comprising the release assembly.
 4. The processingsystem of claim 3, wherein the release assembly comprises a plunger. 5.The processing system of claim 3, wherein the release assembly comprisesone or more nozzles configured to supply a fluid to a backside of thefilm.
 6. The processing system of claim 5, wherein the one or morenozzles comprises a plurality of orifices, wherein a first orifice at afirst end of the release assembly is wider than a second orifice at asecond end of the release assembly.
 7. The processing system of claim 5,wherein the one or more nozzles comprises a plurality of orifices,wherein a first orifice in a central region of the release assembly iswider than orifices at end portions of the release assembly.
 8. Theprocessing system of claim 3, wherein the release assembly comprises afirst collet having a plurality of first fingers spaced apart by one ormore first gaps.
 9. The processing system of claim 8, wherein therelease assembly further comprises a second collet having a plurality ofsecond fingers spaced apart by one or more second gaps, the first andsecond collets configured to move towards and away from one anotheralong the direction.
 10. The processing system of claim 9, wherein thesecond fingers are dimensioned such that, when the first and secondcollets are brought together, at least one second finger is disposedwithin a corresponding first gap and at least one first finger isdisposed within a corresponding second gap.
 11. The processing system ofclaim 1, wherein the control system configured to select a first knowngood element from the plurality of singulated elements, the first knowngood element having properly-functioning non-electrical characteristics,the first element comprising the first known good element.
 12. Theprocessing system of claim 11, wherein the plurality of singulatedelements comprise a plurality of singulated integrated device dies andthe first known good element comprises a first known good die.
 13. Theprocessing system of claims 1, wherein the support structure comprises awafer or wafer stack, a die or die stack, a reconstituted wafer, apanel, a reconstituted panel, a printed circuit board, an interposer, aglass substrate, a plastic substrate, packaging structure, or a ceramicsubstrate.
 14. The processing system of claim 1, wherein the controlsystem is configured to: select a second element from the plurality ofsingulated elements, the second element being different from the firstelement; send instructions to the movable apparatus to cause the movableapparatus to selectively position the film laterally relative to thesupport structure such that the second element is aligned with a secondlocation of the support structure; and send instructions to the releaseassembly to cause the release assembly to apply the force to at leastone of the support structure and the film in the direction nonparallelto the surface of the film to cause the second element to be transferredfrom the film to the support structure, such that the second element isremoved from the film.
 15. The processing system of claim 14, whereinthe second location of the support structure and the first location ofthe support structure are the same and the second element is stacked onthe first element.
 16. The processing system of claim 15, wherein thefirst element and the second element are directly bonded without anintervening adhesive.
 17. The processing system of claim 14, wherein thesecond location is different from the first location and a gap betweenthe first element and the second element is filled with a fillingmaterial.
 18. The processing system of claims 1, wherein the firstelement is directly bonded to the support structure without anintervening adhesive.
 19. The processing system of claims 1, wherein thefilm is wider than at least two singulated elements of the plurality ofsingulated elements.
 20. The processing system of claims 1, wherein thesupport surface of the support structure comprises a web of a substratematerial.